Concrexit user sync and authentication

Authenticate user login against a concrexit instance.

This plugin sync users and group from concrexit to local tables inside NextCloud.

Add the following to your config.php:

    'concrexit' => array(
        'host' => 'https://myconcrexit.example',
        'secret' => 'supersecretapitoken',
        'quota' => '100MB',
    ),

quota is optional option and defaults to 100MB.

And add the plugin code to your custom_apps folder. The plugin should be in a folder called concrexitauth.